This invention relates generally to the field of adjustable pipe wrenches, more particularly to self adjusting pipe wrenches wherein the movable jaw element is spring urged toward its closed position and is held in its open position with a movable lock element which, upon disengagement with the movable jaw, permits the movable jaw to move toward its closed position.
Pipe wrenches usually comprise a handle with a fixed jaw element at one end and a yoke on one side of the handle. The movable jaw element includes a threaded leg member that projects through the yoke, and an internally threaded nut is positioned in the confines of the yoke and about the threaded leg element, so that upon rotation of the nut, the movable jaw is moved toward or away from the fixed jaw. When the wrench is to be used, the worker usually rotates the nut to move the movable jaw so that it forms the desired gap with the fixed jaw, and the jaws are placed about an object. The nut may be further adjusted when the wrench is in position about an object so that the jaws securely grasp the object. When a wrench of this type is used in a small space, the fine adjustment of the wrench is sometimes cumbersome, requiring the operator to remove the wrench from the object so as to be able to rotate the nut of the wrench.
As illustrated in my U.S. Pat. No. 3,996,820, self adjusting pipe wrenches are disclosed in the prior art whereby the movable jaw of the wrench is spring-urged toward its closed relationship with respect to the fixed jaw, and the movable jaw is held in a fixed position by means of a lock element that engages the leg of the movable jaw. Thus, the jaws can be spread apart, the lock element moved to engage and hold the movable jaw in a fixed position, then the jaws of the wrench inserted about an object, the lock element moved to disengage and release the movable jaw whereupon the movable jaw will move against the object and cause the jaws to grasp opposite sides of the element.